RHSA-2015:0867 - Security Advisory

Topic

An updated qemu-kvm package that fixes one security issue and one bug is
now available for Red Hat Enterprise Linux 6.

Red Hat Product Security has rated this update as having Important security
impact. A Common Vulnerability Scoring System (CVSS) base score, which
gives a detailed severity rating, is available from the CVE link in the
References section.

Description

KVM (Kernel-based Virtual Machine) is a full virtualization solution for
Linux on AMD64 and Intel 64 systems. The qemu-kvm package provides the
user-space component for running virtual machines using KVM.

It was found that the Cirrus blit region checks were insufficient. A
privileged guest user could use this flaw to write outside of VRAM-
allocated buffer boundaries in the host's QEMU process address space with
attacker-provided data. (CVE-2014-8106)

This issue was found by Paolo Bonzini of Red Hat.

This update also fixes the following bug:

• Previously, the effective downtime during the last phase of a live

migration would sometimes be much higher than the maximum downtime
specified by 'migration_downtime' in vdsm.conf. This problem has been
corrected. The value of 'migration_downtime' is now honored and the
migration is aborted if the downtime cannot be achieved. (BZ#1142756)

All qemu-kvm users are advised to upgrade to these updated packages, which
contain a backported patch to correct this issue. After installing this
update, shut down all running virtual machines. Once all virtual machines
have shut down, start them again for this update to take effect.

Solution

Before applying this update, make sure all previously released errata
relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 6.6 i386
• Red Hat Enterprise Linux Server - AUS 6.6 x86_64
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux Desktop 6 x86_64
• Red Hat Enterprise Linux Desktop 6 i386
• Red Hat Enterprise Linux for Scientific Computing 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Server - TUS 6.6 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.6 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 6.6 i386
• Red Hat Enterprise Linux EUS Compute Node 6.6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386

Fixes

• BZ - 1169454 - CVE-2014-8106 qemu: cirrus: insufficient blit region checks

CVEs

• CVE-2014-8106

References

• https://access.redhat.com/security/updates/classification/#important